Graphical user interface for a display screen or portion thereof



FIG. 1 is a front view of a graphical user interface for a display screen or portion thereof showing my new design; and,

FIG. 2 is a front view of a second embodiment thereof.

The broken lines showing a portion of a display screen, text and other elements in the Figures are for illustrative purposes only and form no part of the claimed design. 

The ornamental design for a graphical user interface for a display screen or portion thereof, as shown and described. 